Railroad wheels are cast of molten iron or steel in molds and removed therefrom when the metal solidifies but remains hot. The wheels are then heat treated, allowed to cool and inventoried for final machining of an axle hole and delivery to customers for mounting of matched pairs of wheels on axles and car trucks.
The molding process is accurate but does not produce wheels of precisely the same dimensions; and during the molding and heat treating it is possible that a wheel may warp to a degree that will cause it to be unfit for certain types of service or to be scrapped.
Thus before the axle holes are machine finished it is necessary to inspect and test each wheel or warpage,tape size, weight and roundness. (Tape size is an American Association of Railroad Standard of Measuring and Specifying Wheel Circumference.) Heretofore warpage has been checked by laying the wheel on a work surface and lowering a multiple sensor gauging device onto the wheel as shown in U.S. Pat. No. 4,233,745. In another separate prior unit for testing rotundity a device has then been manually rotated around the rim of the wheel as disclosed in U.S. Pat. No. 4,538,357. The procedure has been labor intensive; and gauge movement has risked damage and endangered accuracy. Moreover the wheels are very heavy and have been lifted and moved into and out of position by an overhead hoist or the like.